Fuel pump with inserted pulsator



Dec. 13, 1966 G. B. ELDER ETAL 3,291,065

FUEL PUMP WITH INSERTED PULSATOR Filed May 29, 1964 United States Patent 3,291,065 FUEL PUMI WITH INSERTED PULSATGR Gordon E. Elder, Carl W. Norberg, and Dimitar Toschkoff, all of Flint, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed May 29, 1964, Ser. No. 371,224 1 Claim. (Cl. 10S-150) This invention relates to pumps and more particularly to pumps of the diaphragm type which are specially adapted for providing liquid fuel to internal combustion engines.

A typical diaphragm fuel pump is disclosed in the United States Patent No. 2,868,135 granted January 13, 1959 in the name of Donald R. Reinertson and entitled Fuel Pump with Pulsator. In such pumps it is common to utilize dead air spaces or so-called pulsator chambers by means of which either the inlet iiow or the outlet iiow or both are made more uniform. A yielding mel brane is utilized partially to determine a pulsator chamber and the yielding action eliminates hydraulic knock and increases the flow or efficiency of the pump concerned.

It has now been found that the effect of a pulsator chamber on the inflow or outflow or both of a pump, heretofore subject to fluctuating pressure conditions adverse to pump eiiiciency, may be realized with the use of a simple resilient insert of low cost and reliable performance and as described below.

An object of the present invention is to provide a pump heretofore subject to fluid pressure fluctuations inimical to uniform fluid flow with improved means for eliminating the fluctuations. Another object is to provide a resilient insert for use with a pump to prevent undue pump pressure changes.

A feature of the invention is a pump in which fluid pressure fluctuations are eliminated by means of a resilient insert retained by an inlet tube or an outlet tube in position to cooperate with the pump body in defining a pulsator chamber. Another feature is a resilient insert of rubber-like material specially adapted to be used in a pump.

These and other important features of the invention will now be described in detail in the specification and then pointed out more specifically in the appended claim.

In the drawings:

FIGURE l depicts an elevation view of an automobile type diaphragm fuel pump with pertinent parts drawn in section to illustrate an embodiment of the present invention; and

FIGURE 2 is a perspective enlarged view, a portion being broken away, showing one of the inserts used in the pump assembly shown in FIGURE l.

In FIGURE l, a conventional automobile type diaphragm fuel pump is depicted. This pump is provided with a supporting body comprising a cast upper part 12 and a sheet metal lower part 14 tightly crimped together as at 16 to form a spring chamber 18 and a pumping chamber 20. The pump 10 is adapted to be conventionally operated by an engine-operated cam 22 acting against the outwardly extending end of an arm 24 pivoted on a pin 26 mounted in the pump body. The pheriphery of a pumping diaphragm 28 is clamped between the sheet metal cover 14 and the bottom surface of the top body portion 12 as is conventional and it will be understand that the suction in the pump is generated by limited clockwise rotation of the arm 24 about the pivot pin 26 and that pump pressure in the pumping chamber 20 is developed by a conventional spring 30 acting downice wardly against the diaphragm 28 during counterclockwise rotation of the arm 24.

The sheet metal cover or bottom body portion 14 is tted with two depending cup portions 32 and 34. Each of these is made of sheet metal and serves to enclose a conventional pressure actuated valve 36 or 38. In FIG- URE l the valve 36 is shown as a one-way or inlet valve leading to the pumping chamber 20 and the valve 38 is depicted as a one-way or outlet valve leading to the outlet fitting 44.

Coaxial with the cup-like portion 32 is one end of a right angle inlet tube 40 which extends into the cup-like portion 32. A small block 44 with a protuberance 42 is adapted to serve as an outlet fitting leading from the pump. It will be noted that one end of the inlet tube 4f) and the protuberance 42 each extends an appreciable distance into a liow passage 46 or 4S defined by the cup portions 32 and 34.

The flow passages 46 and 48 are preferably cylindrical and as such they are receptive to inserts Si). In the instant disclosure these inserts are made of the same size and configuration but it will be understood that variations in these respects are possible without departing from the spirit of the present invention. Each insert 50 is made of resilient rubber-like material resistant to the fluid, in the instant case gasoline, being treated, and each insert is preferably made in a cup-like shape with an orifice 51 in its bottom surrounded by inwardly facing annular ridges or small diameter sealing means 52 for gripping the tube 42 or 4G in tiuid-tight relation. The other end of each insert 50 is surrounded with outwardly facing annular ridges 54 adapted tightly to engage the inner wall surface of the fiow passage 46 or 43.

It will be noted that each insert 5f) cooperates with the pump body in defining a fixed annual air chamber 60. This air is trapped or internally sealed behind the flexible membrane made up by the thin wall 62 of the corresponding insert 50. The insert, being of a frusto-conical shape, provides a larger pressure or pulsating area in a very small space. The inserts, being completely internal, could fail or break with extended service but this would not occasion external leakage or a fire hazard or a fuel loss. The pump would still operate and would eliminate any breakdown or interruption in use. The inserts are easily manufactured and at low cost and their insertion during the manufacture of a given fuel pump may be carried out with dispatch.

We claim:

A pump for pumping liquid having a body defining a pumping chamber, a cup-shaped member having an annular portion which forms part of a iiow passage communicating with said pumping chamber, a pressure actuated valve located in said fiow passage and between the pumping chamber and said annular portion, a tube extending into said cup-shaped member and terminating a distance within said member, a resilient generally frustoconical insert disposed within said cup-shaped member, one end of said insert having sealing means comprising inwardly facing annular ridges integral with its inner diameter for sealingly engaging said tube, the other end of said insert having outwardly facing annular ridges integral with the outer diameter of said insert for sealingly engaging said annular portion and thereby defining a closed annular pulse dainpening chamber outside the flow passage and inside said cup-shaped member whereby fluid pulsations are damped as fluid is pumped through the flow passage.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS Dalton 285-110 X McBride 285-110 X Meyer 230-235 Schaefer 103-87 Forster 13S-30 Fitzgerald 103-150 3,150,601 9/1964 smith et a1. 103-223X 3,165,324 11/1965 zop 277-209 3,198,128 8/1965 smith 103-150 5 MARK NEWMAN, Primary Examiner.

WARREN E. COLEMAN, Examiner.

W. L. FREEH, Assistant Examiner. 

